18016321 has 4 divisors (see below), whose sum is σ = 18270144. Its totient is φ = 17762500.

The previous prime is 18016319. The next prime is 18016331. The reversal of 18016321 is 12361081.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18016321 - 2¹ = 18016319 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18016292 and 18016301.

It is not an unprimeable number, because it can be changed into a prime (18016331) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 126805 + ... + 126946.

It is an arithmetic number, because the mean of its divisors is an integer number (4567536).

Almost surely, 2^18016321 is an apocalyptic number.

It is an amenable number.

18016321 is a deficient number, since it is larger than the sum of its proper divisors (253823).

18016321 is an equidigital number, since it uses as much as digits as its factorization.

18016321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253822.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 18016321 is about 4244.5636996045. The cubic root of 18016321 is about 262.1533249746.

The spelling of 18016321 in words is "eighteen million, sixteen thousand, three hundred twenty-one".